Cooling device and system

ABSTRACT

A novel heat pipe and a cooling system that employs the heat pipe are disclosed. The heat pipe has a configuration in the form of a nail that includes a flattened upper section and an elongated lower, section. The heat pipe may be in the form of nail shape or a continuous bar that includes a flattened upper section and an elongated section. The heat pipe may be employed together with a thermoelectric cooling module and a heat sink to provide a cooling device. The cooling device may be employed with a container to provide a cooling system.

FIELD OF THE INVENTION

The present invention relates to refrigeration technology. More particularly, the present invention relates to portable cooling devices and systems.

BACKGROUND OF THE INVENTION

Known mechanical compressor type refrigeration units employ a compressor, a condenser, an evaporator and a fan. These devices, although useful, generate considerable vibration and noise. Also, these devices, owing in part to their size, are not suitable for cooling small amounts of liquids such as found in mugs intended for automobile vehicle use.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in the drawings a form that is presently preferred, it being understood, however, that this invention is not limited to precise arrangements shown.

FIG. 1 is a frontal view of a first embodiment of a heat pipe of the invention;

FIG. 1A is a side view of an a cooling device that shows an alternative embodiment of a heat pipe of the invention;

FIG. 1B is a frontal view of another alternative embodiment of a heat pipe of the invention;

FIG. 1C is a top view of the alternative embodiment shown in FIG. 1B;

FIG. 1D is a top view of the embodiment shown in FIG. 1;

FIG. 2 is a partially exploded, assembly view in of a cooling device that includes the heat pipe of FIG. 1;

FIG. 3 is a partially exploded assembly view of the cooling device of FIG. 2 that includes a holding plate;

FIG. 4 is a side frontal view of the cooling device of FIG. 2 mounted on a drinking mug;

FIG. 5 is a top view of the device shown in FIG. 4.

SUMMARY OF THE INVENTION

The disclosed cooling device 10 employs a heat pipe, such as an elongated heat pipe such as heat pipe 1 in combination with thermoelectric cooling module 2. Heat pipe 1 advantageously may operate in silence and without moving parts. Cooling device 10 advantageously may operate with minimal noise and vibration. Cooling device 10 may be configured to a wide range of dimensions. Advantageously, cooling device 10 may be configured in dimensions suitable for enabling cooling device 10 to be useful as a portable, mini-cooling appliance for use in automotive vehicles, boats, home and office. Cooling device 10 may be configured for battery, DC and AC operation.

DETAILED DESCRIPTION OF THE INVENTION

In a first embodiment, and referring to FIG. 1, heat pipe 1 of the invention has the overall configuration of an elongated nail that has a flattened upper section and an elongated lower section. In this first embodiment, heat pipe 1 includes lower, elongated section 1B and upper section 1A.

Elongated section 1B preferably is in the form of an elongated, hollow cylinder such as a cylinder that has any of a circular cross section or a hollow hexagonal cross section, preferably a hollow circular cross section. When elongated, lower section 1B of heat pipe 1 has a circular cross-section, the inner and outer diameters of lower section 1B may vary over a wide range. Typically, the outer diameter of lower section 1B may vary from about 10 mm to about 20 mm, preferably about 14 mm to about 18 mm. Lower section 1B may have a wall thickness that may vary from about 1 mm to about 2 mm. Where heat pipe 1 is formed from aluminum, the wall thickness is preferably about 1.5 mm and the outer diameter is preferably about 16 mm. The length of section 1B may vary and is limited only by the depth of the container in which the heat pipe is employed. Typically, the length of section 1B is about 80% to about 95% of the depth of the container in which the heat pipe is employed.

Section 1B has an open, upper end and a closed bottom end. The bottom end of section 1B may be configured in a wide variety of shapes. Preferably, the bottom end of lower section 1B is upwardly concave, preferably in the form of a hemisphere. Upper section 1A of heat pipe 1 may have a variety of configurations so as to correspond to the configuration of thermoelectric cooling module 2. Section 1A may have configurations such as square, rectangular, circular, preferably square. Section 1A, as shown in FIG. 1, may include a port, such as port 1C for admitting fluid such as coolant into heat pipe 1 for receipt into lower section 1B. The coolant employed in the heat pipe typically is a phase change, heat transfer liquid such as ammonia, acetone, R134a from DuPont (1,1,1,2-Tetrafluoroethane), HFO-1234yf from DuPont (2,3,3,3-tetrafluoroprop-1-ene), ethanol and mixtures thereof.

The upper surface of elongated section 1B may be joined to the bottom surface of upper section 1A by a variety of methods such as welding, brazing and the like to form a leak resistant, preferably a leak-proof assembly. Upper section 1A also may be integral with elongated section 1B as may be produced by methods such as casting.

Each of elongated section 1B and upper section 1A may be formed from the same or different, heat conductive materials, preferably the same heat conductive materials. Useful heat conductive materials typically have thermal conductivities of about 150W·m⁻¹·K⁻¹ or greater at 300 K. Examples of these heat conductive materials include but are not limited to aluminum and copper, preferably aluminum, as well as bi-layer composites of aluminum and copper. Where copper is employed, the copper may be nickel-plated or chrome plated. Where aluminum is employed, the aluminum may be anodized, preferably hard anodized. Where bi-layer materials of aluminum and copper are employed in any of elongated section 1B and upper section 1A of heat pipe 1, copper is preferably on the interior of elongated section 1B. Where bi-layer materials of aluminum and copper are employed for upper section 1A, copper is preferably employed on the exterior of upper section 1A. Heat pipe 1 is suitable for use in a container such as container 13 shown in FIG. 4. Typically, section 1B has a length that is about 80% to about 95% of the depth of the container in which the heat pipe is employed

Elongated section 1B, as shown in FIGS. 1B and 1C, may include one or more cooling fins 1G. Spacings between adjacent cooling fins 1G may be uniform or non-uniform, preferably uniform. Fins 1G may extend over any desired length of lower section 1B, preferably about 70% to about 85% of the length of lower section 1B.

In a second embodiment, and as shown in FIG. 1A, heat pipe 1 may have the configuration of a continuous angled bar that has an upper section 1D that is integral with a longer, lower section 1E. Preferably, upper section 1D has a length that is less that the length of the lower section 1E. The angle θ between upper section 1D and lower section 1E may be about 90°±about 10°, preferably about 90°. The angled bar preferably is formed from aluminum and has a ratio of width to thickness of about 3 to about 6, preferably about 3 to about 4. Typically, the bar has a width of about 30 mm to about 40 mm and a thickness of about 6 mm to about 10 mm. The bar includes one or a plurality of channels, preferably a plurality of channels, more preferably a plurality of channels that have a diameter of about 3 mm to about 6 mm, preferably a diameter of about 3.5 mm to about 4 that extend the throughout the total length of the upper section 1D and the lower section 1E. The channels may be of the same or different diameter. The pitch between the channels is about 1.5 times to about 2 times the diameter of the holes. Each end of the bar may be sealed by brazing or welding.

Upper section 1D may vary over a wide range of dimensions and configurations. Typically, section 1D has dimensions of length and width that are about equal to that of thermoelectric cooling module 2. Section 1D may have configurations such as square, rectangular, circular, preferably square. The dimensions of section 1E also may vary over a wide range. Typically, section 1E has a length that is about 80% to about 95% of the depth of the container in which the heat pipe is employed. The bar may be formed of conductive metals such as aluminum, copper, or bi-layers of aluminum and copper, preferably aluminum.

Referring to FIGS. 1 to 5, cooling device 10 employs heat pipe 1 together with thermoelectric cooling module 2, heat sink 3 and fan 4. Thermoelectric cooling module 2 may have a variety of configurations. Preferably, thermoelectric cooling module 2 has a square configuration. An example of thermoelectric cooling module 2 that has a square cross section for use in cooling device 10 is NORD Corp. thermoelectric cooling module # TM-127-1.4-6.0. thermoelectric cooling module 2 is secured to the top surfaces of sections 1A, 1D of heat pipes 1 so that the cold surface of thermoelectric cooling module 2 contacts the top surfaces of the upper sections of heat pipe 1, such as the upper sections 1A,1D of heat pipe 1. Thermoelectric cooling module 2 may be secured to the upper surface of heat pipe 1 by mechanical fasteners such as screws, and the like, preferably screws. Heat sink 3 is secured to the top of thermoelectric cooling module 2 so as to contact the upper surface of thermoelectric cooling module 2. Heat sink 3 may be secured to the upper surface of thermoelectric cooling module 2 by any one or more of mechanical fasteners such as screws, and the like, preferably screws. Heat sink 3 preferably is in the form of an air-cooled heat sink that includes a plurality of cooling fins 3A. This type of heat sink is available from AAVID.

Fan 4, such as a muffin fan from SUNON, is secured to heat sink 3. Fan 4 generates forced air to dissipate heat from heat sink 3. Fan 4 may be secured to heat sink 3 by mechanical fasteners such as screws.

Heat pipe 1, thermoelectric cooling module 2, and heat sink 3 that has fan 4 mounted thereon are secured to holding plate 8 by fasteners such as screws 9 to form an assembly. Holding plate 8 may be formed from conductive materials such as metal or insulating materials such as plastics. Optional insulation cubes 7 formed of materials such as non-metallic insulative materials such as nylon may be secured together with heat pipe 1, thermoelectric cooling module 2 and heat sink 3 to holding plate 8 by fasteners such as screws 9. Thermal insulation foam optionally may be provided between the bottom surface of heat sink 3 and the top surface of holding plate 8.

In use, cooling device 10, as shown in FIG. 4, may be mounted on container 13 to form a cooling system suitable for use at home and office as well as in a motor vehicle. Container 13 may be of any desired configuration, preferably a cylindrical container. Container 13 typically has flowable material therein, such as liquid, to be chilled by cooling device 10.

Container 13, as shown in FIG. 4, optionally may be equipped with a tube 14 such as a straw for extracting material from container 13. Container 13 may include removable lid 11 for supply of material to container 13. Cooling device 10 may be secured to lid 11 of container 13 by fasteners such as screws, clips, and the like. Lid 11 may include a seal ring to aid in sealing of lid 11 to container 13. Lid 11, on the bottom thereof, may include a flexible, rubber type sealant 12 to aid in securing cooling device 10 to container 13. Cooling device 10 may include a 12V DC socket 15 for connection to a power supply or a power outlet such as that of an automobile for powering of thermoelectric cooling module 2 and fan 4.

During use, heat pipe 1 of cooling device 10 is inserted into a flowable material to be cooled, such as a liquid such as water in container 13. Heat from the flowable material is transferred to heat pipe 1 to cause evaporation of the coolant in heat pipe 1, the vapor rises upwardly until it reaches the cold surface of the upper section of heat pipe 1. The latent heat of the coolant vapor is transferred to thermoelectric cooling module 2 whereby the vapor condenses and falls to the bottom of heat pipe 1 for subsequent cycling and continued cooling of the material in container 13. 

1. A heat pipe comprising a flattened upper section operatively connected to an elongated lower section wherein the elongated lower section has the configuration on an elongated hollow cylinder.
 2. The heat pipe of claim 1 wherein the elongated hollow cylinder has a circular cross section or a hollow hexagonal cross section.
 3. The heat pipe of claim 1 wherein the lower section has a closed lower end and an open upper end wherein the closed lower end has a hemispherical configuration.
 4. The heat pipe of claim 1 wherein the upper section includes a port for admitting coolant into the lower section.
 5. The heat pipe of claim 4 wherein the coolant is a phase change, heat transfer liquid selected from the group consisting of ammonia, acetone, 1,1,1,2-Tetrafluoroethane, 2,3,3,3-tetrafluoroprop-1-ene, ethanol and mixtures thereof.
 6. The heat pipe of claim 1 wherein each of the elongated section and the upper section are formed from heat conductive materials that have thermal conductivities of about 150W·m⁻¹·K⁻¹ or greater at 300 K.
 7. The heat pipe of claim 6 wherein the heat conductive materials are aluminum.
 8. A heat pipe comprising a continuous angled bar that has an upper section that is integral with an elongated lower section wherein the upper section and lower section have an angle θ there between and wherein the bar has at least one channel that extends throughout the upper section and the lower section.
 9. The heat pipe of claim 8 wherein the bar has a ratio of width to thickness of about 3 to about
 6. 10. The heat pipe of claim 8 wherein the bar includes a plurality of channels.
 11. The heat pipe of claim 8 wherein the angle θ is about 90°±10°.
 12. A cooling device comprising a heat pipe cooperatively connected to a thermoelectric cooling module wherein the thermoelectric cooling module is cooperatively connected to a heat sink and wherein the thermoelectric cooling module generates a cold surface that contacts the heat pipe to cool fluid coolant in the heat pipe.
 13. The device of claim 12 further comprising a fan unit cooperatively connected the heat sink wherein the fan unit provides air to the heat sink.
 14. A cooling system comprising the cooling device of claim 12 secured to a container suitable for retaining flowable material wherein the heat pipe extends into the container.
 15. The cooling system of claim 14 wherein the cooling device of claim 12 further comprises a fan unit cooperatively connected to the heat sink wherein the fan unit provides air to the heat sink.
 16. The cooling system of claim 14 further comprising a tube for extracting flowable material from the container. 